Skip to main content
Biology LibreTexts

6.14G: Filtration

  • Page ID
    9217
    • Boundless
    • Boundless
    \( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\)

    Fluids that would be damaged by heat, irradiation, or chemical sterilization can be sterilized by microfiltration using membrane filters.

    LEARNING OBJECTIVES

    Demonstrate microbial control using filtration

    Key Takeaways

    Key Points

    • A typical microfiltration membrane pore size range is 0.1-10 µm, with the most commonly used being 0.2 µm and 0.45 µm, which is sufficient to eliminate bacteria and fungi.
    • Quite often, when biological samples are processed, viruses must be removed or inactivated. Nanofilters with smaller pore sizes of 20-50 nm (nanofiltration) are used.
    • Filtration is commonly used for heat labile pharmaceuticals and protein solutions in processing medicines. It is also increasingly used in the treatment of drinking water.

    Key Terms

    • ester: An ester is a chemical compound consisting of a carbonyl group adjacent to an ether linkage.
    • polyethersulfone: Thermoplastic polymers that have low protein retention. They contain the subunit aryl-SO2-aryl, the defining feature of which is the sulfone group.

    Fluids that would be damaged by heat (such as fluids containing proteins like large molecule drug products, but also wine and beer), irradiation, or chemical sterilization can only be sterilized by microfiltration using membrane filters. This method is commonly used for heat labile pharmaceuticals and for protein solutions in processing medicines.

    The typical microfiltration membrane pore size range is 0.1-10 µm, with the most commonly used being 0.2 µm; and 0.45 µm is sufficient to eliminate bacteria and fungi.

    image
    Figure: Syringe Filter: A syringe filter with a pore size of 0.22 micrometers, small enough to capture and retain bacterial and fungal cells.

    Microfiltration is increasingly used in drinking water treatment. It effectively removes major pathogens and contaminants such as Giardia lamblia cysts, Cryptosporidium oocysts, and large bacteria. For this application, the filter has to be rated for 0.2 µm or smaller pore size.

    Quite often when biological samples are processed, viruses must be removed or inactivated. Nanofilters with smaller pore sizes of 20-50 nm (nanofiltration) are used. The smaller the pore size, the lower the flow rate. To achieve higher total throughput or avoid premature blockage, pre-filters might be used to protect small pore membrane filters. Some studies have shown that prions can be removed or reduced by filtration.

    Membrane filters used in production processes are commonly made from materials such as mixed cellulose ester or polyethersulfone. The filtration equipment and the filters may be purchased as pre-sterilized disposable units in sealed packaging, or must be sterilized by the user, generally by autoclaving at a temperature that does not damage the fragile filter membranes. To ensure proper functioning of the filter, the membrane filters are integrity tested post-use or sometimes pre-use. A non-destructive integrity test assures the filter is undamaged, and is also a regulatory requirement enforced by agencies like the Food and Drug Administration, the European Medicines Agency, and others.

    LICENSES AND ATTRIBUTIONS

    CC LICENSED CONTENT, SPECIFIC ATTRIBUTION

    • Dry heat sterilization. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Dry_heat_sterilization. License: CC BY-SA: Attribution-ShareAlike
    • Sterilization (microbiology). Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Sterili...(microbiology). License: CC BY-SA: Attribution-ShareAlike
    • Moist heat sterilization. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Moist_heat_sterilization. License: CC BY-SA: Attribution-ShareAlike
    • sterilization. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/sterilization. License: CC BY-SA: Attribution-ShareAlike
    • Boundless. Provided by: Boundless Learning. Located at: www.boundless.com//microbiology/definition/tyndallisation. License: CC BY-SA: Attribution-ShareAlike
    • AUTOCLAVE 4210. Provided by: Wikimedia. Located at: commons.wikimedia.org/wiki/Fi...CLAVE_4210.jpg. License: Public Domain: No Known Copyright
    • Sterilization (microbiology). Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Sterilization_(microbiology). License: CC BY-SA: Attribution-ShareAlike
    • Ultraviolet germicidal irradiation. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Ultraviolet_germicidal_irradiation. License: CC BY-SA: Attribution-ShareAlike
    • NRC. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/NRC. License: CC BY-SA: Attribution-ShareAlike
    • Graft-versus-host disease. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Graft-versus-host%20disease. License: CC BY-SA: Attribution-ShareAlike
    • AUTOCLAVE 4210. Provided by: Wikimedia. Located at: commons.wikimedia.org/wiki/Fi...CLAVE_4210.jpg. License: Public Domain: No Known Copyright
    • UV-ontsmetting laminaire-vloeikast. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/File:UV...-vloeikast.JPG. License: Public Domain: No Known Copyright
    • Physical factors affecting microbial life. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Physical_factors_affecting_microbial_life. License: CC BY-SA: Attribution-ShareAlike
    • Physical factors affecting microbial life. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Physical_factors_affecting_microbial_life. License: CC BY-SA: Attribution-ShareAlike
    • Psychrophile. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Psychrophile. License: CC BY-SA: Attribution-ShareAlike
    • Frozen food. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Frozen_food. License: CC BY-SA: Attribution-ShareAlike
    • proliferation. Provided by: Wiktionary. Located at: en.wiktionary.org/wiki/proliferation. License: CC BY-SA: Attribution-ShareAlike
    • AUTOCLAVE 4210. Provided by: Wikimedia. Located at: commons.wikimedia.org/wiki/Fi...CLAVE_4210.jpg. License: Public Domain: No Known Copyright
    • UV-ontsmetting laminaire-vloeikast. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/File:UV...-vloeikast.JPG. License: Public Domain: No Known Copyright
    • SS Dunedin by Frederick Tudgay. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/File:SS...ick_Tudgay.JPG. License: Public Domain: No Known Copyright
    • Pascalization. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Pascalization. License: CC BY-SA: Attribution-ShareAlike
    • Physical factors affecting microbial life. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Physical_factors_affecting_microbial_life. License: CC BY-SA: Attribution-ShareAlike
    • bridgmanization. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/bridgmanization. License: CC BY-SA: Attribution-ShareAlike
    • AUTOCLAVE 4210. Provided by: Wikimedia. Located at: commons.wikimedia.org/wiki/File:AUTOCLAVE_4210.jpg. License: Public Domain: No Known Copyright
    • UV-ontsmetting laminaire-vloeikast. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/File:UV...-vloeikast.JPG. License: Public Domain: No Known Copyright
    • SS Dunedin by Frederick Tudgay. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/File:SS...ick_Tudgay.JPG. License: Public Domain: No Known Copyright
    • Tonjiru.asahimatsu.namamisozui. Provided by: Wikimedia. Located at: commons.wikimedia.org/wiki/Fi...amamisozui.jpg. License: CC BY-SA: Attribution-ShareAlike
    • Freeze-drying. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Freeze-drying. License: CC BY-SA: Attribution-ShareAlike
    • Freeze-drying. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Freeze-drying. License: CC BY-SA: Attribution-ShareAlike
    • Freeze-drying. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Freeze-drying. License: CC BY-SA: Attribution-ShareAlike
    • Desiccation. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Desiccation. License: CC BY-SA: Attribution-ShareAlike
    • Deinococcus radiodurans. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Deinococcus_radiodurans. License: CC BY-SA: Attribution-ShareAlike
    • Drying (food). Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Drying_(food). License: CC BY-SA: Attribution-ShareAlike
    • freeze-drying. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/freeze-drying. License: CC BY-SA: Attribution-ShareAlike
    • Boundless. Provided by: Boundless Learning. Located at: www.boundless.com//biology/de...on/desiccation. License: CC BY-SA: Attribution-ShareAlike
    • AUTOCLAVE 4210. Provided by: Wikimedia. Located at: commons.wikimedia.org/wiki/File:AUTOCLAVE_4210.jpg. License: Public Domain: No Known Copyright
    • UV-ontsmetting laminaire-vloeikast. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/File:UV-ontsmetting_laminaire-vloeikast.JPG. License: Public Domain: No Known Copyright
    • SS Dunedin by Frederick Tudgay. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/File:SS...ick_Tudgay.JPG. License: Public Domain: No Known Copyright
    • Tonjiru.asahimatsu.namamisozui. Provided by: Wikimedia. Located at: commons.wikimedia.org/wiki/Fi...amamisozui.jpg. License: CC BY-SA: Attribution-ShareAlike
    • SMART Freeze Dryer. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/File:SM...eeze_Dryer.png. License: Public Domain: No Known Copyright
    • Osmotic pressure. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Osmotic_pressure. License: CC BY-SA: Attribution-ShareAlike
    • Food preservation. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Food_preservation. License: CC BY-SA: Attribution-ShareAlike
    • Curing (food preservation). Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Curing_..._preservation). License: CC BY-SA: Attribution-ShareAlike
    • Turgor pressure. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Turgor_pressure. License: CC BY-SA: Attribution-ShareAlike
    • Sugaring. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Sugaring. License: CC BY-SA: Attribution-ShareAlike
    • Osmotic pressure. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Osmotic_pressure. License: CC BY-SA: Attribution-ShareAlike
    • Sugaring. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Sugaring. License: CC BY-SA: Attribution-ShareAlike
    • turgidity. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/turgidity. License: CC BY-SA: Attribution-ShareAlike
    • AUTOCLAVE 4210. Provided by: Wikimedia. Located at: commons.wikimedia.org/wiki/File:AUTOCLAVE_4210.jpg. License: Public Domain: No Known Copyright
    • UV-ontsmetting laminaire-vloeikast. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/File:UV-ontsmetting_laminaire-vloeikast.JPG. License: Public Domain: No Known Copyright
    • SS Dunedin by Frederick Tudgay. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/File:SS_Dunedin_by_Frederick_Tudgay.JPG. License: Public Domain: No Known Copyright
    • Tonjiru.asahimatsu.namamisozui. Provided by: Wikimedia. Located at: commons.wikimedia.org/wiki/Fi...amamisozui.jpg. License: CC BY-SA: Attribution-ShareAlike
    • SMART Freeze Dryer. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/File:SM...eeze_Dryer.png. License: Public Domain: No Known Copyright
    • Salami aka. Provided by: Wikimedia. Located at: commons.wikimedia.org/wiki/File:Salami_aka.jpg. License: CC BY-SA: Attribution-ShareAlike
    • Nanofiltration. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Nanofiltration. License: CC BY-SA: Attribution-ShareAlike
    • Sterilization (microbiology). Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Sterilization_(microbiology). License: CC BY-SA: Attribution-ShareAlike
    • Microfiltration. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Microfiltration. License: CC BY-SA: Attribution-ShareAlike
    • Syringe filter. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Syringe_filter. License: CC BY-SA: Attribution-ShareAlike
    • polyethersulfone. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/polyethersulfone. License: CC BY-SA: Attribution-ShareAlike
    • ester. Provided by: Wiktionary. Located at: en.wiktionary.org/wiki/ester. License: CC BY-SA: Attribution-ShareAlike
    • AUTOCLAVE 4210. Provided by: Wikimedia. Located at: commons.wikimedia.org/wiki/File:AUTOCLAVE_4210.jpg. License: Public Domain: No Known Copyright
    • UV-ontsmetting laminaire-vloeikast. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/File:UV-ontsmetting_laminaire-vloeikast.JPG. License: Public Domain: No Known Copyright
    • SS Dunedin by Frederick Tudgay. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/File:SS_Dunedin_by_Frederick_Tudgay.JPG. License: Public Domain: No Known Copyright
    • Tonjiru.asahimatsu.namamisozui. Provided by: Wikimedia. Located at: commons.wikimedia.org/wiki/File:Tonjiru.asahimatsu.namamisozui.jpg. License: CC BY-SA: Attribution-ShareAlike
    • SMART Freeze Dryer. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/File:SMART_Freeze_Dryer.png. License: Public Domain: No Known Copyright
    • Salami aka. Provided by: Wikimedia. Located at: commons.wikimedia.org/wiki/File:Salami_aka.jpg. License: CC BY-SA: Attribution-ShareAlike
    • Syringe filter-0,22-um-Millex-GV-05. Provided by: Wikimedia. Located at: commons.wikimedia.org/wiki/Fi...llex-GV-05.jpg. License: CC BY-SA: Attribution-ShareAlike

    This page titled 6.14G: Filtration is shared under a CC BY-SA 4.0 license and was authored, remixed, and/or curated by Boundless.

    • Was this article helpful?